Can't Upgrade. Always Offline!

I've been trying to upgrade since early March! First visit, they were offline. Second visit.....offline!! Third visit.....told that they can't upgrade because I'm on a postpaid contract and the only contracts available are top up contracts, so either I pay more (for a tailor-made contract) or wait until end April. I go today.....OFFLINE!!!! I try and phone Cell C retentions/sales.....I hold for 8mins, then I try again....hold for another 15mins! So I hang up! So once again I miss out on the Friday offers. And if I go next Friday, then we're already into May and it messes with Billing. That is IF they aren't OFFLINE.......AGAIN!!!! Absolutely shocking!!! If you don't want my business just say so!!!!!!!!!! They have become such a disappointment over the last year!